Related Clues:

• Open a little container with key, initially
• Hardly open, as a door
• Cracked just slightly
• It could contain jam but is certainly not jammed
• Permitting peeking, perhaps
• Open a pot of jam?
• Open-ish, as a door
• Just a little cracked
• Almost closed, doorwise
• Left open
• Not merely unlocked
• Admitting the draught, perhaps, is a bit of a shock
• Part-open
• Like a door facilitating eavesdropping, say
• Unlatched, say